Molecular weight controls the elongation of oblate-shaped degradable poly(γ-benzyl-L-glutamate)nanoparticles

The shape of nanoparticles in drug targeting applications has been recently suggested as being an interesting parameter for modulating their fate in the body after delivery. In view of investigating the incidence of this parameter on in vivo distribution, poly(γ-benzyl-L-glutamate) (PBLG) has been selected for preparing non-spherical nanoparticles. PBLG is a degradable polymer forming α-helices rods, which can easily self-assemble by nanoprecipitation into oblate-shaped nanoparticles. Varying the molecular weight of the polymer from 28 to 85 kg mol(-1) resulted in elongation ratios between 1.5 and 3.5, respectively, while the nanoparticles exhibited a fairly constant particle volume. Their non spherical shape was attributed to an ordered packing of the PBLG rods resulting in a liquid crystal-like self organization of PBLG rods with varying lengths. This set of morphological characteristics makes these nanoparticles a valuable tool for gaining a better understanding of their fate in biological fluids, mechanisms of interactions with cells and in vivo distribution studies.